unit.getRecolor new_pixel;
add_burn_shade new_pixel burn shade;
return new_pixel;
This is default script lined to each unit, if you replace script in given unit by this, then on its own will not change behavior of shading at all.
But when you replace it, you can alter it any way you want and archive your desired result.
In this case if you replace parameter `shade` usage by `0` then game will display given unit as it was in bright light.